This proposal is to establish a Coordinating Center for a multicenter study to test the hypothesis that a rnulticomponent school-based and community- linked intervention can prevent a decline in physical activity levels and cardiorespiratory fitness in middle school girls. The importance of physical activity in promoting health and preventing disease is well documented. Physical inactivity has been identified as an independent risk factor for obesity, cardiovascular disease, type 2diabetes and osteoporosis. Population surveys from the United States consistently demonstrate that youth activity levels fail to meet recommended guidelines for physical activity participation. There is no question that the declines in physical activity that have been observed in American youth need to be reversed, and that this problem is most critical in girls. Linked school and community-based interventions hold promise for increasing levels of physical activity and fitness in adolescent girls, however, effective programs need to be developed and tested. The TAAG study will address this critical need. The Coordinating Center will coordinate study activities; facilitate and contribute to the development of the interventions, measurements and the study protocol; provide expertise in study design and biostatistics; perform all data analysis; prepare and distribute intervention materials, forms and manuals of operation; develop and support web-based systems to serve the study; develop and implement plans for acquisition, transfer and management of data; develop and implement a student tracking system; organize and conduct training for field center staff; organize, analyze and report quality control of the measurements and interventions, collaborate in the preparation of scientific publications and presentations and serve as a repository for study materials and data. The staff of the proposed coordinating center is multidisciplinary with faculty from the Departments of Biostatistics, Epidemiology, Nutrition, Exercise Science, Health Behavior, Health Education and the School of Medicine.